In general, no, nothing prohibits surface clipped twin with earth to a socket outlet or for some other purpose.
There might be a prohibition under certain circumstances, for example if the cable exposed to undue risk of damage.
There might also be a CONTRACTUAL prohibition, if for example the client or the consultant or architect says “no surface wiring” or even “no twin with earth” then this instruction must be respected.
In general, no, nothing prohibits surface clipped twin with earth to a socket outlet or for some other purpose.
There might be a prohibition under certain circumstances, for example if the cable exposed to undue risk of damage.
There might also be a CONTRACTUAL prohibition, if for example the client or the consultant or architect says “no surface wiring” or even “no twin with earth” then this instruction must be respected.
